Method and system for vagal blocking with or without vagal stimulation to provide therapy for obesity and other gastrointestinal disorders using rechargeable implanted pulse generator

ABSTRACT

Method and system to provide therapy for obesity and gastrointestinal disorders such as FGIDs, gastroparesis, gastro-esophageal reflex disease (GERD), pancreatitis and ileus comprises vagal blocking and/or vagal stimulation, utilizing implanted and external components. Vagal blocking may be in the afferent or efferent direction, and may be with or without selective stimulation. Blocking may be provided by one of a number of different electrical blocking techniques. The implantable components are a lead and an implantable pulse generator (IPG), comprising re-chargeable lithium-ion or lithium-ion polymer battery. The external components are a programmer and an external recharger. In one embodiment, the implanted pulse generator may also comprise stimulus-receiver means, and a pulse generator means with rechargeable battery. In another embodiment, the implanted pulse generator is adapted to be rechargeable, utilizing inductive coupling with an external recharger. Existing nerve stimulators may also be adapted to be used with rechargeable power sources as disclosed herein. The implanted system comprises a lead with two or more electrodes, for vagus nerve(s) modulation with selective stimulation and/or blocking. In another embodiment, the external stimulator and/or programmer may comprise an optional telemetry unit. The addition of the telemetry unit to the external stimulator and/or programmer provides the ability to remotely interrogate and change stimulation programs over a wide area network, as well as other networking capabilities.

This application is a continuation of application Ser. No. 11/035,374filed Jan. 13, 2005, entitled “Method and system for providingelectrical pulses for neuromodulation of vagus nerve(s) usingrechargeable implanted pulse generator”, which is a continuation ofapplication Ser. No. 10/841,995 filed May 8, 2004, which is acontinuation of application Ser. No. 10/196,533 filed Jul. 16, 2002,which is a continuation of application Ser. No. 10/142,298 filed on May9, 2002. The prior applications being incorporated herein in entirety byreference, and priority is claimed from these applications.

FIELD OF INVENTION

This invention relates generally to providing electrical pulses forblocking/stimulation therapy for medical disorders, more specifically toneuromodulation therapy comprising vagal blocking with or without vagalstimulation, for providing therapy for obesity and othergastrointestinal (GI) disorders, utilizing rechargeable implantablepulse generator.

Background of Obesity and Relation to Vagus Nerve

Obesity is a significant health problem in the United States and manyother developed countries. Obesity results from excessive accumulationof fat in the body. It is caused by ingestion of greater amounts of foodthan can be used by the body for energy. The excess food, whether fats,carbohydrates, or proteins, is then stored almost entirely as fat in theadipose tissue, to be used later for energy. Obesity is not simply theresult of gluttony and a lack of willpower. Rather, each individualinherits a set of genes that control appetite and metabolism, and agenetic tendency to gain weight that may be exacerbated by environmentalconditions such as food availability, level of physical activity andindividual psychology and culture. Other causes of obesity also includepsychogenic, neurogenic, and other metabolic related factors.

Obesity is defined in terms of body mass index (BMI), which provides anindex of the relationship between weight and height. The BMI iscalculated as weight (in Kilograms) divided by height (in squaremeters), or as weight (in pounds) times 703 divided by height (in squareinches). The primary classification of overweight and obesity relates tothe BMI and the risk of mortality. The prevalence of obesity in adultsin the United States without coexisting morbidity increased from 12% in1991 to 17.9% in 1998, and is still increasing.

Treatment of obesity depends on decreasing energy input below energyexpenditure. Treatment has included among other things various drugs,starvation, and even stapling or surgical resection of a portion of thestomach. Surgery for obesity has included gastroplasty and gastricbypass procedure. Gastroplasty which is also known as stomach stapling,involves constructing a 15- to 30 mL pouch along the lesser curvature ofthe stomach. A modification of this procedure involves the use of anadjustable band that wraps around the proximal stomach to create a smallpouch. Both gastroplasty and gastric bypass procedures have a number ofcomplications.

The vagus nerve (which is the 10^(th) cranial nerve) plays a role inmediating afferent information from the stomach to the satiety center inthe brain. The vagus nerve arises directly from the brain, but unlikethe other cranial nerves extends well beyond the head. At its farthestextension it reaches the lower parts of the intestines. This is shownschematically in FIG. 1, and in more detail in FIG. 2.

In 1988 it was reported in the American Journal of Physiology, that theafferent vagal fibers from the stomach wall increased their firing ratewhen the stomach was filled. One way to look at this regulatory processis to imagine that the drive to eat, which may vary rather slowly withthe rise and fall of hormone Leptin, is inhibited by satiety signalsthat occur when we eat and begin the digestive process (i.e., theprandial period). As shown schematically in FIG. 3, these satietysignals both terminate the meal and inhibit feeding for some timeafterward. During this postabsorptive (fasting) period, the satietysignals slowly dissipate until the drive to eat again takes over.

The regulation of feeding behavior involves the concentrated action ofseveral satiety signals such as gastric distention, the release of thegastrointestinal peptide cholecystokinin (CCK), and the release of thepancreatic hormone insulin. The stomach wall is richly innervated bymechanosensory axons, and most of these ascend to the brain via thevagus nerve(s) 54. The vagus sensory axons activate neurons in theNucleus of the Solitary Tract in the medulla of the brain. These signalsinhibit feeding behavior. In a related mechanism, the peptide CCK isreleased in response to stimulation of the intestines by certain typesof food, especially fatty ones. CCK reduces frequency of eating and sizeof meals. As depicted schematically in FIG. 4, both gastric distensionand CCK act synergistically to inhibit feeding behavior.

Vagal Blocking and/or Stimulation

In commonly assigned disclosures, application Ser. No. 10/079,21 nowU.S. Pat. ______, and U.S. Pat. No. 6,611,715, pulsed electricalneuromodulation therapy for obesity and other medical conditions isobtained by providing electrical pulses to the vagus nerve(s) via animplanted lead comprising plurality of electrodes. In those disclosures,the electrical pulses are provided by at least one electrode on thelead. This patent application is directed to system and method forneuromodulation of vagal activity, wherein vagal block with or withoutselective vagal stimulation may be used to provide therapy for obesity,weight loss, eating disorders, and other gastrointestinal disorders suchas FGIDs, gastroparesis, gastro-esophageal reflex disease (GERD),pancreatitis, ileus and the like. Even though the invention is disclosedin the context of vagal blocking, the nerve blocking methodology canalso be used to provide therapy for other ailments, and to provideelectric pulses for blocking of other nerves such as sympatheticnerve(s), sacral nerves, or other cranial nerves or their branches orpart thereof.

The gastrointestinal tract and central nervous system (CNS) engage eachother in two-way communication. This has both parasympathetic andsympathetic components. Of particular interest in this disclosure is theparasympathetic component or the vagal pathway, which is shown inconjunction with FIG. 5.

In some gastrointestinal (GI) disorders, to provide therapy, stimulationof the vagus nerve(s) is adequate and is the preferred mode of providingtherapy. For other GI disorders, to provide therapy, stimulation andselective block is the preferred mode of therapy. For some GI disorders,vagal nerve(s) blocking only is the preferred mode of providing therapy.Advantageously, the method and system disclosed in this patentapplication can provide vagal blocking with or without vagal stimulationto provide therapy for obesity and other gastrointestinal disorders.

As is shown in conjunction with FIG. 6 when vagal pathway is stimulated,the stimulation is conducted both in the Afferent (towards the brain)and Efferent (away from the brain) direction. Shown in conjunction withFIG. 7, by placing blocking electrodes proximal to the stimulatingelectrodes, and supplying blocking pulses, the conduction in theAfferent direction (towards the brain) can be blocked or significantlyreduced. The blocking pulses may be 500 Hz or other frequency, asdescribed later in this disclosure. This is useful for certain GIdisorders, for example ileus and the like.

Shown in conjunction with FIG. 8, the blocking electrodes may be placeddistal to the stimulating electrodes. If the stimulator providesblocking pulses to the blocking electrode, then the vagus nerve(s)impulses in the Efferent direction are either blocked or aresignificantly reduced. As the vagus nerves are involved in pancreatitus,the down-regulating of vagal activity can be used to treat pancreatitusand the like.

It will be clear to one of ordinary skill in the art, that byselectively placing the blocking electrode, selective block can beobtained when the stimulator applies blocking pulses to the blockingelectrode. Selective Efferent block is depicted in conjunction with FIG.9. As shown in the figure, because of the selective placement ofblocking electrode(s), only the impulses to visceral organ 2 are blockedor significantly reduced, and impulses to visceral organ-1 and visceralorgan-2 continue unimpeded. Selective Afferent block can also beachieved, and is depicted in conjunction with FIG. 10. Here the nerveimpulses to visceral organ and visceral organ-5 are selectively blocked.An example would be where Afferent vagal pulses are desired, butimpulses to the heart and vocal cords would be blocked. Thus,advantageously providing the desired therapy without the side effects ofvoice or cardiac complications such as bradycardia. Similarly other sideeffects can be alleviated or minimized with nerve blocking.

Background of Neuromodulation

Most nerves in the human body are composed of thousands of fibers ofdifferent sizes. This is shown schematically in FIG. 11. The differentsizes of nerve fibers, which carry signals to and from the brain, aredesignated by groups A, B, and C. The vagus nerve, for example, may haveapproximately 100,000 fibers of the three different types, each carryingsignals. Each axon or fiber of that nerve conducts only in onedirection, in normal circumstances. In the vagus nerve sensory fibersoutnumber parasympathetic fibers four to one.

In a cross section of peripheral nerve it is seen that the diameter ofindividual fibers vary substantially, as is also shown schematically inFIG. 12. The largest nerve fibers are approximately 20 μm in diameterand are heavily myelinated (i.e., have a myelin sheath, constituting asubstance largely composed of fat), whereas the smallest nerve fibersare less than 1 μm in diameter and are unmyelinated.

The diameters of group A and group B fibers include the thickness of themyelin sheaths. Group A is further subdivided into alpha, beta, gamma,and delta fibers in decreasing order of size. There is some overlappingof the diameters of the A, B, and C groups because physiologicalproperties, especially in the form of the action potential, are takeninto consideration when defining the groups. The smallest fibers (groupC) are unmyelinated and have the slowest conduction rate, whereas themyelinated fibers of group B and group A exhibit rates of conductionthat progressively increase with diameter.

Nerve cells have membranes that are composed of lipids and proteins, andhave unique properties of excitability such that an adequate disturbanceof the cell's resting potential can trigger a sudden change in themembrane conductance. Under resting conditions, the inside of the nervecell is approximately −90 mV relative to the outside. The electricalsignaling capabilities of neurons are based on ionic concentrationgradients between the intracellular and extracellular compartments. Thecell membrane is a complex of a bilayer of lipid molecules with anassortment of protein molecules embedded in it, separating these twocompartments. Electrical balance is provided by concentration gradientswhich are maintained by a combination of selective permeabilitycharacteristics and active pumping mechanism.

A nerve cell can be excited by increasing the electrical charge withinthe neuron, thus increasing the membrane potential inside the nerve withrespect to the surrounding extracellular fluid. The threshold stimulusintensity is the value at which the net inward current (which is largelydetermined by Sodium ions) is just greater than the net outward current(which is largely carried by Potassium ions), and is typically around−55 mV inside the nerve cell relative to the outside (critical firingthreshold). If however, the threshold is not reached, the gradeddepolarization will not generate an action potential and the signal willnot be propagated along the axon. This fundamental feature of thenervous system i.e., its ability to generate and conduct electricalimpulses, can take the form of action potentials, which are defined as asingle electrical impulse passing down an axon. This action potential(nerve impulse or spike) is an “all or nothing” phenomenon, that is tosay once the threshold stimulus intensity is reached, an actionpotential will be generated.

To stimulate an excitable cell, it is only necessary to reduce thetransmembrane potential by a critical amount. When the membranepotential is reduced by an amount ΔV, reaching the critical or thresholdpotential. When the threshold potential is reached, a regenerativeprocess takes place: sodium ions enter the cell, potassium ions exit thecell, and the transmembrane potential falls to zero (depolarizes),reverses slightly, and then recovers or repolarizes to the restingmembrane potential (RMP). For a stimulus to be effective in producing anexcitation, it must have an abrupt onset, be intense enough, and lastlong enough.

Cell membranes can be reasonably well represented by a capacitance C,shunted by a resistance R as shown by an electrical model in FIG. 13,where neuronal process is divided into unit lengths, which isrepresented in an electrical equivalent circuit. Each unit length of theprocess is a circuit with its own membrane resistance (r_(m)), membranecapacitance (c_(m)), and axonal resistance (r_(a)).

When the stimulation pulse is strong enough, an action potential will begenerated and propagated. As shown in FIG. 14, the action potential istraveling from right to left. Immediately after the spike of the actionpotential there is a refractory period when the neuron is eitherunexcitable (absolute refractory period) or only activated tosub-maximal responses by supra-threshold stimuli (relative refractoryperiod). The absolute refractory period occurs at the time of maximalSodium channel inactivation while the relative refractory period occursat a later time when most of the Na⁺ channels have returned to theirresting state by the voltage activated K⁺ current. The refractory periodhas two important implications for action potential generation andconduction. First, action potentials can be conducted only in onedirection, away from the site of its generation, and secondly, they canbe generated only up to certain limiting frequencies.

A single electrical impulse passing down an axon is shown schematicallyin FIG. 15. The top portion of the figure (A) shows conduction overmylinated axon (fiber) and the bottom portion (B) shows conduction overnonmylinated axon (fiber). These electrical signals will travel alongthe nerve fibers.

The information in the nervous system is coded by frequency of firingrather than the size of the action potential. In terms of electricalconduction, myelinated fibers conduct faster, are typically larger, havevery low stimulation thresholds, and exhibit a particularstrength-duration curve or respond to a specific pulse width versusamplitude for stimulation, compared to unmyelinated fibers. The A and Bfibers can be stimulated with relatively narrow pulse widths, from 50 to200 microseconds (μs), for example. The A fiber conducts slightly fasterthan the B fiber and has a slightly lower threshold. The C fibers arevery small, conduct electrical signals very slowly, and have highstimulation thresholds typically requiring a wider pulse width(300-1,000 μs) and a higher amplitude for activation. Because of theirvery slow conduction, C fibers would not be highly responsive to rapidstimulation. Selective stimulation of only A and B fibers is readilyaccomplished. The requirement of a larger and wider pulse to stimulatethe C fibers, however, makes selective stimulation of only C fibers, tothe exclusion of the A and B fibers, virtually unachievable inasmuch asthe large signal will tend to activate the A and B fibers to some extentas well.

As shown in FIG. 16, when the distal part of a nerve is electricallystimulated, a compound action potential is recorded by an electrodelocated more proximally. A compound action potential contains severalpeaks or waves of activity that represent the summated response ofmultiple fibers having similar conduction velocities. The waves in acompound action potential represent different types of nerve fibers thatare classified into corresponding functional categories as shown in theTable one below, TABLE 1 Conduction Fiber Fiber Velocity Diameter Type(m/sec) (μm) Myelination A Fibers Alpha  70-120 12-20 Yes Beta 40-70 5-12 Yes Gamma 10-50 3-6 Yes Delta  6-30 2-5 Yes B Fibers  5-15 <3 YesC Fibers 0.5-2.0 0.4-1.2 No

Vagus nerve blocking and stimulation, performed by the system and methodof the current patent application, is a means of directly affectingcentral function, as well as, peripheral function. FIG. 17 shows cranialnerves have both afferent pathway 19 (inward conducting nerve fiberswhich convey impulses toward the brain) and efferent pathway 21 (outwardconducting nerve fibers which convey impulses to an effector). Vagusnerve (the 10^(th) cranial nerve) is composed of 80% afferent sensoryfibers carrying information to the brain from the head, neck, thorax,and abdomen. The sensory afferent cell bodies of the vagus reside in thenodose ganglion and relay information to the nucleus tractus solitarius(NTS).

The vagus nerve spans from the brain stem all the way to the splenicflexure of the colon. Not only is the vagus the parasympathetic nerve tothe thoracic and abdominal viscera, it also the largest visceral sensory(afferent) nerve. Sensory fibers outnumber parasympathetic fibers fourto one. In the medulla, the vagal fibers are connected to the nucleus ofthe tractus solitarius (viceral sensory), and three other nuclei. Thecentral projections terminate largely in the nucleus of the solitarytract, which sends fibers to various regions of the brain (e.g., thethalamus, hypothalamus and amygdala).

This application is also related to co-pending applications entitled“METHOD AND SYSTEM FOR PROVIDING ELECTRICAL PULSES TO GASTRIC WALL OF APATIENT WITH RECHARGEABLE IMPLANTABLE PULSE GENERATOR FOR TREATING ORCONTROLLING OBESITY AND EATING DISORDERS” and “METHOD AND SYSTEM TOPROVIDE THERAPY FOR OBESITY AND OTHER MEDICAL DISORDERS, BY PROVIDINGELECTRICAL PULSES TO SYMPATHETIC NERVES OR VAGAL NERVE(S) WITHRECHARGEABLE IMPLANTED PULSE GENERATOR.

PRIOR ART

Prior art is generally directed to adapting cardiac pacemaker technologyfor nerve stimulation, where U.S. Pat. Nos. 5,263,480 (Wernicke et al.)and 5,188,104 (Wernicke et al.) are generally directed to treatment ofeating disorders with vagus nerve stimulation using an implantableneurocybernetic prosthesis (NCP), which is a “cardiac pacemaker-like”device. There is no disclosure for vagal blocking.

U.S. Pat. No. 5,540,730 (Terry et al.) is generally directed to treatingmotility disorders with vagus nerve stimulation using an implantableneurocybernetic prosthesis (NCP), which is a “cardiac pacemaker-like”device.

U.S. Pat. No. 6,553,263B1 (Meadows et al.) is generally directed to animplantable pulse generator system for spinal cord stimulation, whichincludes a rechargeable battery. In the Meadows '263 patent there is nodisclosure or suggestion for combing a stimulus-receiver module to animplantable pulse generator (I PG) for use with an external stimulator,for providing modulating pulses to sympathetic nerve(s), as in theapplicant's disclosure.

U.S. Pat. No. 6,505,077 B1 (Kast et al.) is directed to electricalconnection for external recharging coil. In the Kast '077 disclosure, amagnetic shield is required between the externalized coil and the pulsegenerator case. In one embodiment of the applicant's disclosure, theexternalized coil is wrapped around the pulse generator case, withoutrequiring a magnetic shield.

U.S. Pat. No. 6,600,954 B2 (Cohen et al.) is generally directed toselectively blocking propagation of body-generated action potentialsparticularly useful for pain control.

U.S. Pat. No. 6,684,105 B2 (Cohen et al.) is generally directed to anapparatus for unidirectional nerve stimulation.

U.S. Pat. No. 6,611,715 B1 (Boveja) is generally directed to a systemand method to provide therapy for obesity and compulsive eatingdisorders using an implantable lead-receiver and an external stimulator.

SUMMARY OF THE INVENTION

The method and system of the current invention overcomes manyshortcomings of the prior art by providing a system for neuromodulationwith extended power source either in the form of rechargeable battery,or by utilizing an external stimulator in conjunction with an implantedpulse generator device, to provide therapy for obesity, motilitydisorders, eating disorders, inducing weight loss, FGIDs, gastroparesis,gastro-esophageal reflex disease (GERD), pancreatitis, and ileus.

Accordingly, in one aspect of the invention, electrical pulses areprovided utilizing a rechargeable implantable pulse generator for nerveblocking, with or without selective electrical stimulation of vagusnerve(s) or its branches or part thereof for treating obesity and otherGI disorders.

In another aspect of the invention, the electrical pulses are providedfor at least one of afferent block, efferent block, or organ block.

In another aspect of the invention, the nerve blocking comprises atleast one from a group consisting of: DC or anodal block, Wedenskiblock, and Collision block.

In another aspect of the invention, a coil used in recharging said pulsegenerator is around the implantable pulse generator case, and in asilicone enclosure.

In another aspect of the invention, the rechargeable implanted pulsegenerator comprises two feedthroughs.

In another aspect of the invention, the rechargeable implanted pulsegenerator comprises only one feed-through for externalizing the rechargecoil.

In another aspect of the invention, the implantable rechargeable pulsegenerator comprises stimulus-receiver means such that, the implantablerechargeable pulse generator can function in conjunction with anexternal stimulator, to provide nerve blocking with or without selectiveelectrical stimulation of vagus nerve(s) or its branches or partthereof.

In another aspect of the invention, the rechargeable battery comprisesat least one of lithium-ion, lithium-ion polymer batteries.

In another aspect of the invention, the external programmer or theexternal stimulator comprises networking capabilities for remotecommunications over a wide area network for remote interrogation and/orremote programming.

In yet another aspect of the invention, the implanted lead comprises atleast two electrode(s) which are made of a material selected from thegroup consisting of platinum, platinum/iridium alloy, platinum/iridiumalloy coated with titanium nitride, and carbon.

This and other objects are provided by one or more of the embodimentsdescribed below.

BRIEF DESCRIPTION OF THE DRAWINGS

For the purpose of illustrating the invention, there are shown inaccompanying drawing forms which are presently preferred, it beingunderstood that the invention is not intended to be limited to theprecise arrangement and instrumentalities shown.

FIG. 1 is a diagram depicting vagal nerves in a patient.

FIG. 2 is a diagram showing vagal nerve innervation to the viceralorgans.

FIG. 3 is a schematic diagram showing the relationship of meals andsatiety signals.

FIG. 4 is a schematic diagram showing impulses traveling via the vagusnerve in response to gastric distention and CCK release.

FIG. 5 is a diagram depicting two-way communication between the gut andcentral nervous system (CNS).

FIG. 6 is a diagram showing conduction of nerve impulses in bothafferent and efferent direction with artificial electrical stimulation.

FIG. 7 is a diagram depicting blocking in the afferent direction, butconducting in the efferent direction with electrical stimulation.

FIG. 8 is a diagram depicting electrical stimulation with conduction inthe afferent direction and blocking in the efferent direction.

FIG. 9 is a diagram depicting electrical stimulation with conduction inthe afferent direction and selective organ blocking in the efferentdirection.

FIG. 10 is a diagram depicting electrical stimulation with conduction inthe efferent direction and selective organ blocking in the afferentdirection.

FIG. 11 is a diagram of the structure of a nerve.

FIG. 12 is a diagram showing different types of nerve fibers.

FIG. 13 is a schematic illustration of electrical circuit model of nervecell membrane.

FIG. 14 is an illustration of propagation of action potential in nervecell membrane.

FIG. 15 is an illustration showing propagation of action potential alonga myelinated axon and non-myelinated axon.

FIG. 16 is a diagram showing recordings of compound action potentials.

FIG. 17 is a schematic diagram of brain showing afferent and efferentpathways.

FIG. 18 is a diagram of implanted components of stimulation/blockingsystem with multiple electrodes around anterior and posterior vagalnerves.

FIG. 19A is a diagram showing the implanted components (rechargeableimplantable pulse generator), and an external stimulator coupled toimplanted stimulus-receiver.

FIG. 19B is a diagram showing placement of the external (primary) coilin relation of the implanted stimulus-receiver.

FIG. 20 is a simplified general block diagram of an implantable pulsegenerator.

FIG. 21A shows energy density of different types of batteries.

FIG. 21B shows discharge curves for different types of batteries.

FIG. 22 shows a block diagram of an implantable stimulator which can beused as a stimulus-receiver or an implanted pulse generator withrechargeable battery.

FIG. 23 is a block diagram highlighting battery charging circuit of theimplantable stimulator of FIG. 22.

FIG. 24 is a schematic diagram highlighting stimulus-receiver portion ofimplanted stimulator of one embodiment.

FIG. 25 depicts externalizing recharge and telemetry coil from thetitanium case.

FIG. 26A depicts coil around the titanium case with two feedthroughs fora bipolar configuration.

FIG. 26B depicts coil around the titanium case with one feedthrough fora unipolar configuration.

FIG. 26C depicts two feedthroughs for the external coil which are commonwith the feedthroughs for the lead terminal.

FIG. 26D depicts one feedthrough for the external coil which is commonto the feedthrough for the lead terminal.

FIGS. 27A and 27B depict recharge coil on the titanium case with amagnetic shield in-between.

FIG. 28 shows a rechargeable implantable pulse generator in blockdiagram form.

FIG. 29 depicts in block diagram form, the implanted and externalcomponents of an implanted rechargable system.

FIG. 30 depicts the alignment function of rechargable implantable pulsegenerator.

FIG. 31 is a block diagram of the external recharger.

FIG. 32A is a schematic diagram of an implantable lead with threeelectrodes.

FIG. 32B is a schematic diagram of an implantable lead with multipleelectrodes.

FIG. 32C is a schematic diagram of an implantable lead with twoelectrodes.

FIG. 33 is a schematic diagram of the pulse generator and two-waycommunication through a server.

FIG. 34 is a diagram depicting wireless remote interrogation andprogramming of the external pulse generator.

FIG. 35 is a schematic diagram of the wireless protocol.

FIG. 36 is a simplified block diagram of the networking interface board.

FIGS. 37A and 37B are simplified diagrams showing communication ofmodified PDA/phone with an external stimulator via a cellular tower/basestation.

DESCRIPTION OF THE INVENTION

To provide vagal blocking and/or vagal stimulation therapy to a patient,blocking and stimulation electrodes are implanted at the appropriatesites. In one preferred embodiment, without limitation, multipleelectrodes comprising both blocking and stimulation electrodes areplaced in a band. As shown in conjunction with FIG. 18, the bandcomprising multiple electrodes is wrapped around the esophagus, close tothe junction of esophagus and the stomach 5 (just below the diaphragm).Alternatively, the individual electrodes do not have to be in a band,and may be individual electrodes, connected to the body of the lead viainsulated conductors (shown in FIG. 32B). In such a case, the portion ofthe electrode contacting the nerve tissue would be exposed and the restof the electrode being insulated with a non-conductive material such assilicone or polyurethane. Such electrodes are well known in the art.

The electrodes may be implanted using laproscopic surgery oralternatively a surgical exposure may be made for implantation of theelectrodes at the appropriate site to be stimulated and/or blocked.After placing the electrodes, the terminal portion of the lead istunneled to a subcutaneous site where the electronics package is to beimplanted. The terminal end of the lead is connected to the rechargeableimplantable pulse generator. The patient is surgically closed in layers,and electrical pulse delivery can begin once the patient has fullyrecovered from the surgery.

In the method and system of this invention, stimulation without blockmay be provided. Additionally, stimulation with selective block may beprovided. Furthermore, block alone (without stimulation) may beprovided, which would be functionally equivalent to reversible vagotomy.

Blocking of nerve impulses, unidirectional blocking, and selectiveblocking of nerve impulses is well known in the scientific literature.Some of the general literature is listed below and is incorporatedherein by reference. (a) “Generation of unidirectionally propagatingaction potentials using a monopolar electrode cuff”, Annals ofBiomedical Engineering, volume 14, pp. 437-450, By Ira J. Ungar et al.(b) “An asymmetric two electrode cuff for generation of unidirectionallypropagated action potentials”, IEEE Transactions on BiomedicalEngineering, volume BME-33, No. 6, June 1986, By James D. Sweeney, etal. (c) A spiral nerve cuff electrode for peripheral nerve stimulation,IEEE Transactions on Biomedical Engineering, volume 35, No. 11, November1988, By Gregory G. Naples. et al. (d) “A nerve cuff technique forselective excitation of peripheral nerve trunk regions, IEEETransactions on Biomedical Engineering, volume 37, No. 7, July 1990, ByJames D. Sweeney, et al. (e) “Generation of unidirectionally propagatedaction potentials in a peripheral nerve by brief stimuli”, Science,volume 206 pp. 1311-1312, Dec. 14, 1979, By Van Den Honert et al. (f “Atechnique for collision block of perpheral nerve: Frequency dependence”IEEE Transactions on Biomedical Engineering, MP-12, volume 28, pp.379-382, 1981, By Van Den Honert et al. (g) “A nerve cuff design for theselective activation and blocking of myelinated nerve fibers” Ann. Conf.of the IEEE Engineering in Medicine and Biology Soc., volume 13, No. 2,p 906, 1991, By D. M Fitzpatrick et al. (h) “Orderly recruitment ofmotoneurons in an acute rabbit model”, “Ann. Conf. of the IEEEEngineering in Medicine and Biology Soc., volume 20, No. 5, page 2564,1998, By N. J. M. Rijkhof, et al. (i) “Orderly stimulation of skeletalmuscle motor units with tripolar nerve cuff electrode”, IEEETransactions on Biomedical Engineering, volume 36, No. 8, pp. 836,1989,By R. Bratta. (j) M. Devor, “Pain Networks”, Handbook of Brand Theoryand Neural Networks, Ed. M. A. Arbib, MIT Press, page 698, 1998.

Blocking can be generally divided into 3 categories: (a) DC or anodalblock, (b) Wedenski Block, and (c) Collision block. In anodal blockthere is a steady potential which is applied to the nerve causing areversible and selective block. In Wedenski Block the nerve isstimulated at a high rate causing the rapid depletion of theneurotransmitter. In collision blocking, unidirectional actionpotentials are generated anti-dromically. The maximal frequency forcomplete block is the reciprocal of the refractory period plus thetransit time, i.e. typically less than a few hundred hertz. The use ofany of these blocking techniques can be applied for the practice of thisinvention, and all are considered within the scope of this invention.

FIGS. 19A and 19B depict the implantable components of the system. Arechargeable implantable pulse generator 391R is connected to the lead40 for delivering pulses via multiple electrodes in contact with nervetissue. The selective blocking and/or stimulation to the vagal nervetissue 54 can be performed by “pre-determined” programs stored in thememory, or by “customized” programs where the electrical parameters areselectively programmed for specific therapy to the individual patient.The electrical parameters which can be individually programmed, includevariables such as pulse amplitude, pulse width, frequency ofstimulation, type of pulse (e.g. blocking pulses may be sinusoidal),stimulation on-time, and stimulation off-time. Table two below definesthe approximate range of parameters, TABLE 2 Electrical parameter rangedelivered to the nerve for stimulation and/or blocking PARAMER RANGEPulse Amplitude 0.1 Volt-10 Volts Pulse width 20 μS-5 mSec. Stim.Frequency 5 Hz-200 Hz Freq. for blocking DC to 5,000 Hz On-time 5Secs-24 hours Off-time 5 Secs-24 hours

The parameters in Table 2 are the electrical signals delivered to thenerve tissue via the two stimulation electrodes 61,62 (or blockingelectrodes) at the nerve tissue 54.

Shown in conjunction with FIG. 20, is an overall schematic of a generalimplantable pulse generator system to deliver electrical pulses formodulating the vagus nerve(s) (selective stimulation and/or blocking)and providing therapy. The implantable pulse generator unit 391 is amicroprocessor based device, where the entire circuitry is encased in ahermetically sealed titanium can. As shown in the overall block diagram,the logic & control unit 398 provides the proper timing for the outputcircuitry 385 to generate electrical pulses that are delivered to a pairof electrodes via a lead 40. Timing is provided by oscillator 393. Thepair of electrodes to which the stimulation energy is delivered isswitchable. Programming of the implantable pulse generator (IPG) 391 isdone via an external programmer 85. Once programmed via an externalprogrammer 85, the implanted pulse generator 391 provides appropriateelectrical blocking and/or stimulation pulses to the vagal nerve(s) 54via the blocking/stimulating electrodes 61,62,63.

Because of the high energy requirements for the pulses required forblocking and/or selective stimulation of vagal nerve tissue 54, there isa real need for power sources that will provide an acceptable servicelife under conditions of continuous delivery of high frequency pulses.FIG. 21A shows a graph of the energy density of several commonly usedbattery technologies. Lithium batteries have by far the highest energydensity of commonly available batteries. Also, a lithium batterymaintains a nearly constant voltage during discharge. This is shown inconjunction with FIG. 21B, which is normalized to the performance of thelithium battery. Lithium-ion batteries also have a long cycle life, andno memory effect. However, Lithium-ion batteries are not as tolerant toovercharging and overdischarging. One of the most recent development inrechargable battery technology is the Lithium-ion polymer battery.Recently the major battery manufacturers (Sony, Panasonic, Sanyo) haveannounced plans for Lithium-ion polymer battery production.

For preferred method of the current invention, two embodiments ofimplantable pulse generators may be used. Both embodiments comprisere-chargeable power sources, such as Lithium-ion polymer battery.

In one embodiment of this invention, the implanted stimulator comprisesa stimulus-receiver module and a pulse generator module. Advantageously,this embodiment provides an ideal power source, since the power sourcecan be an external stimulator in conjunction with an implantedstimulus-receiver, or the power source can be from the implantedrechargable battery 740. Shown in conjunction with FIG. 22 is asimplified overall block diagram of this embodiment. A coil 48C which isexternal to the titanium case may be used both as a secondary of astimulus-receiver, or may also be used as the forward and back telemetrycoil. The coil 48C may be externalized at the header portion 79C of theimplanted device, and may be wrapped around the titanium case,eliminating the need for a magnetic shield. In this case, the coil isencased in the same material as the header 79C. Alternatively, the coilmay be positioned on the titanium case, with a magnetic shield.

In this embodiment, as disclosed in FIG. 22, the IPG circuitry withinthe titanium case is used for all stimulation pulses whether the energysource is the internal rechargeable battery 740 or an external powersource. The external device serves as a source of energy, and as aprogrammer that sends telemetry to the IPG. For programming, the energyis sent as high frequency sine waves with superimposed telemetry wavedriving the external coil 46C. The telemetry is passed through couplingcapacitor 727 to the IPG's telemetry circuit 742. For pulse deliveryusing external power source, the stimulus-receiver portion will receivethe energy coupled to the implanted coil 48C and, using the powerconditioning circuit 726, rectify it to produce DC, filter and regulatethe DC, and couple it to the IPG's voltage regulator 738 section so thatthe IPG can run from the externally supplied energy rather than theimplanted battery 740.

The system provides a power sense circuit 728 that senses the presenceof external power communicated with the power control 730, when adequateand stable power is available from an external source. The power controlcircuit controls a switch 736 that selects either implanted rechargeablebattery power 740 or conditioned external power from 726. The logic andcontrol section 732 and memory 744 includes the IPG's microcontroller,pre-programmed instructions, and stored changeable parameters. Usinginput for the telemetry circuit 742 and power control 730, this sectioncontrols the output circuit 734 that generates the output pulses.

Shown in conjunction with FIG. 23, this embodiment of the invention ispracticed with a rechargeable battery 740. This circuit is energizedwhen external power is available. It senses the charge state of thebattery and provides appropriate charge current to safely recharge thebattery without overcharging. Recharging circuitry is described later.

The stimulus-receiver portion of the circuitry is shown in conjunctionwith FIG. 24. Capacitor C1 (729) makes the combination of C1 and L1sensitive to the resonant frequency and less sensitive to otherfrequencies, and energy from an external (primary) coil 46C isinductively transferred to the implanted unit via the secondary coil48C. The AC signal is rectified to DC via diode 731, and filtered viacapacitor 733. A regulator 735 set the output voltage and limits it to avalue just above the maximum IPG cell voltage. The output capacitor C4(737), typically a tantalum capacitor with a value of 100 micro-Faradsor greater, stores charge so that the circuit can supply the IPG withhigh values of current for a short time duration with minimal voltagechange during a pulse while the current draw from the external sourceremains relatively constant. Also shown in conjunction with FIGS. 23 and24, a capacitor C3 (727) couples signals for forward and back telemetry.

In another embodiment, existing implantable pulse generators can bemodified to incorporate rechargeable batteries. As shown in conjunctionwith FIG. 25, in both embodiments, the coil is externalized from thetitanium case 57. The RF pulses transmitted via coil 46 and received viasubcutaneous coil 48A are rectified via a diode bridge. These DC pulsesare processed and the resulting current applied to recharge the battery694/740 in the implanted pulse generator. In one embodiment the coil 48may be externalized at the header portion 79C of the implanted device,and may be wrapped around the titanium case, as shown in FIGS. 26A and26B. Shown in FIG. 26A is a bipolar configuration which requires twofeedthroughs 76,77. Advantageously, as shown in FIG. 26B unipolarconfiguration may also be used which requires only one feedthrough 75.The other end is electronically connected to the case. In both cases,the coil is encased in the same material as the header 79.Advantageously, as shown in conjunction with FIGS. 26C and 26D, thefeedthrough for the coil can be combined with the feedthrough for thelead terminal. This can be applied both for bipolar and unipolarconfigurations.

In one embodiment, the coil may be positioned on the titanium case asshown in conjunction with FIGS. 27A and 27B. FIG. 27A shows a diagram ofthe finished implantable stimulator 391R of one embodiment. FIG. 27Bshows the pulse generator with some of the components used in assemblyin an exploded view. These components include a coil cover 13, thesecondary coil 48 and associated components, a magnetic shield 9, and acoil assembly carrier 11. The coil assembly carrier 11 has at least onepositioning detail 80 located between the coil assembly and the feedthrough for positioning the electrical connection. The positioningdetail 80 secures the electrical connection in this embodiment.

A schematic diagram of the implanted pulse generator (IPG 391R), withre-chargeable battery 694 of one preferred embodiment of this invention,is shown in conjunction with FIG. 28. The IPG 391R includes logic andcontrol circuitry 673 connected to memory circuitry 691. The operatingprogram and stimulation parameters are typically stored within thememory 691 via forward telemetry. Blocking/stimulation pulses areprovided to the nerve tissue 54 via output circuitry 677 controlled bythe microcontroller.

The operating power for the IPG 391R is derived from a rechargeablepower source 694. The rechargeable power source 694 comprises arechargeable lithium-ion or lithium-ion polymer battery. Rechargingoccurs inductively from an external charger to an implanted coil 48Bunderneath the skin 60. The rechargeable battery 694 may be rechargedrepeatedly as needed. Additionally, the IPG 391R is able to monitor andtelemeter the status of its rechargeable battery 691 each time acommunication link is established with the external programmer 85.

Much of the circuitry included within the IPG 391R may be realized on asingle application specific integrated circuit (ASIC). This allows theoverall size of the IPG 391R to be quite small, and readily housedwithin a suitable hermetically-sealed case. The IPG case is preferablymade from titanium and is shaped in a rounded case.

Shown in conjunction with FIG. 29 are the recharging elements of theinvention. The recharging system uses a portable external charger tocouple energy into the power source of the IPG 391R. The DC-to-ACconversion circuitry 696 of the recharger receives energy from a battery672 in the recharger. A charger base station 680 and conventional ACpower line may also be used. The AC signals amplified via poweramplifier 674 are inductively coupled between an external coil 46B andan implanted coil 48B located subcutaneously with the implanted pulsegenerator (IPG) 391R. The AC signal received via implanted coil 48B isrectified 686 to a DC signal which is used for recharging therechargable battery 694 of the IPG, through a charge controller IC 682.Additional circuitry within the IPG 391R includes, battery protection IC688 which controls a FET switch 690 to make sure that the rechargablebattery 694 is charged at the proper rate, and is not overcharged. Thebattery protection IC 688 can be an off-the-shelf IC available fromMotorola (part no. MC 33349N-3R1). This IC monitors the voltage andcurrent of the implanted rechargable battery 694 to ensure safeoperation. If the battery voltage rises above a safe maximum voltage,the battery protection IC 688 opens charge enabling FET switches 690,and prevents further charging. A fuse 692 acts as an additionalsafeguard, and disconnects the battery 694 if the battery chargingcurrent exceeds a safe level. As also shown in FIG. 29, chargecompletion detection is achieved by a back-telemetry transmitter 684,which modulates the secondary load by changing the full-wave rectifierinto a half-wave rectifier/voltage clamp. This modulation is in turn,sensed by the charger as a change in the coil voltage due to the changein the reflected impedance. When detected through a back telemetryreceiver 676, either an audible alarm is generated or a LED is turnedon.

A simplified block diagram of charge completion and misalignmentdetection circuitry is shown in conjunction with FIG. 30. As shown, aswitch regulator 686 operates as either a full-wave rectifier circuit ora half-wave rectifier circuit as controlled by a control signal (CS)generated by charging and protection circuitry 698. The energy inducedin implanted coil 48B (from external coil 46B) passes through the switchrectifier 686 and charging and protection circuitry 698 to the implantedrechargable battery 694. As the implanted battery 694 continues to becharged, the charging and protection circuitry 698 continuously monitorsthe charge current and battery voltage. When the charge current andbattery voltage reach a predetermined level, the charging and protectioncircuitry 698 triggers a control signal. This control signal causes theswitch rectifier 686 to switch to half-wave rectifier operation. Whenthis change happens, the voltage sensed by voltage detector 702 causesthe alignment indicator 706 to be activated. This indicator 706 may bean audible sound or a flashing LED type of indicator.

The indicator 706 may similarly be used as a misalignment indicator. Innormal operation, when coils 46B (external) and 48B (implanted) areproperly aligned, the voltage V_(s) sensed by voltage detector 704 is ata minimum level because maximum energy transfer is taking place. If andwhen the coils 46B and 48B become misaligned, then less than a maximumenergy transfer occurs, and the voltage V_(s) sensed by detectioncircuit 704 increases significantly. If the voltage V_(s) reaches apredetermined level, alignment indicator 706 is activated via an audiblespeaker and/or LEDs for visual feedback. After adjustment, when anoptimum energy transfer condition is established, causing V_(s) todecrease below the predetermined threshold level, the alignmentindicator 706 is turned off.

The elements of the external recharger are shown as a block diagram inconjunction with FIG. 31. The charger base station 680 receives itsenergy from a standard power outlet 714, which is then converted to 5volts DC by a AC-to-DC transformer 712. When the recharger is placed ina charger base station 680, the rechargable battery 672 of the rechargeris fully recharged in a few hours and is able to recharge the battery694 of the IPG 391R. If the battery 672 of the external recharger fallsbelow a prescribed limit of 2.5 volt DC, the battery 672 is tricklecharged until the voltage is above the prescribed limit, and then atthat point resumes a normal charging process.

As also shown in FIG. 31, a battery protection circuit 718 monitors thevoltage condition, and disconnects the battery 672 through one of theFET switches 716, 720 if a fault occurs until a normal conditionreturns. A fuse 724 will disconnect the battery 672 should the chargingor discharging current exceed a prescribed amount.

Referring now to FIG. 32A, the implanted lead component of the system issimilar to cardiac pacemaker leads, except for distal portion (orelectrode end) of the lead. This figure depicts a lead with tripolarelectrodes 62,61,63 for stimulation and/or blocking. FIG. 32B shows alead with multiple pairs of electrodes (63, 62, 61). Differentelectrodes or electrode pairs are used for blocking or for stimulation,as directed by logic and control unit 673 of rechargeable implantablepulse generator 691R. An alternative embodiment with a pair ofelectrodes 61, 62 is also shown in FIG. 32C. The lead terminalpreferably is linear bipolar, even though it can be bifurcated, andplug(s) into the cavity of the pulse generator means. The lead body 59insulation may be constructed of medical grade silicone, siliconereinforced with polytetrafluoro-ethylene (PTFE), or polyurethane. Theelectrodes 61,62,63 for stimulating/blocking the vagus nerve 54 mayeither wrap around the nerve or may be adapted to be in contact withtissue to be blocked/stimulated. These stimulating electrodes may bemade of pure platinum, platinum/Iridium alloy or platinum/iridium coatedwith titanium nitride. The conductor connecting the terminal to theelectrodes 61,62 is made of an alloy of nickel-cobalt. The implantedlead design variables are also summarized in table four below. TABLE 4Lead design variables Proximal Distal End End Conductor (connecting Leadbody- proximal Lead Insulation and distal Electrode - Electrode -Terminal Materials Lead-Coating ends) Material Type Linear PolyurethaneAntimicrobial Alloy of Pure Wrap-around bipolar coating Nickel- Platinumelectrodes Cobalt Bifurcated Silicone Anti- Platinum- Standard BallInflammatory Iridium and Ring coating (Pt/Ir) Alloy electrodes Siliconewith Lubricious Pt/Ir coated Steroid Polytetrafluoroethylene coatingwith Titanium eluting (PTFE) Nitride Carbon

Once the lead is fabricated, coating such as anti-microbial,anti-inflammatory, or lubricious coating may be applied to the body ofthe lead.

Telemetry Module

Shown in conjunction with FIG. 33, in one embodiment of the inventionthe external stimulator 42 and/or programmer 85 may comprise two-waywireless communication capabilities with a remote server, using acommunication protocol such as the wireless application protocol (WAP).The purpose of the telemetry module is to enable the physician toremotely, via the wireless medium change the programs, activate, ordisengage programs. Additionally, schedules of therapy programs, can beremotely transmitted and verified. Advantageously, the physician is thusable to remotely control the stimulation therapy.

FIG. 34 is a simplified schematic showing the communication aspectsbetween the external stimulator 42 and or programmer 85, and the remotehand-held computer. A desktop or laptop computer can be a server 130which is situated remotely, perhaps at a health-care provider's facilityor a hospital. The data can be viewed at this facility or reviewedremotely by medical personnel on a wireless internet supported hand-helddevice 140, which could be a personal data assistant (PDA), for example,a “palm-pilot” from PALM corp. (Santa Clara, Calif.), a “Visor” fromHandspring Corp. (Mountain view, CA) or on a personal computer (PC)available from numerous vendors or a cell phone or a handheld devicebeing a combination thereof. The physician or appropriate medicalpersonnel, is able to interrogate the external stimulator 42 device andknow what the device is currently programmed to, as well as, get agraphical display of the pulse train. The wireless communication withthe remote server 130 and hand-held device (wireless internet supported)140 can be achieved in all geographical locations within and outside theUnited States (US) that provides cell phone voice and data communicationservice. The pulse generation parameter data can also be viewed on thehandheld devices 140.

The telecommunications component of this invention uses WirelessApplication Protocol (WAP). WAP is a set of communication protocolsstandardizing Internet access for wireless devices. Previously,manufacturers used different technologies to get Internet on hand-helddevices. With WAP, devices and services inter-operate. WAP promotesconvergence of wireless data and the Internet. The WAP Layers areWireless Application Environment (WAE), Wireless Session Layer (WSL),Wireless Transport Layer Security (WTLS) and Wireless Transport Layer(WTP).

The WAP programming model, which is heavily based on the existingInternet programming model, is shown schematically in FIG. 35.Introducing a gateway function provides a mechanism for optimizing andextending this model to match the characteristics of the wirelessenvironment. Over-the-air traffic is minimized by binaryencoding/decoding of Web pages and readapting the Internet Protocolstack to accommodate the unique characteristics of a wireless mediumsuch as call drops. Such features are facilitated with WAP.

The key components of the WAP technology, as shown in FIG. 35,includes 1) Wireless Mark-up Language (WML) 400 which incorporates theconcept of cards and decks, where a card is a single unit of interactionwith the user. A service constitutes a number of cards collected in adeck. A card can be displayed on a small screen. WML supported Web pagesreside on traditional Web servers. 2) WML Script which is a scriptinglanguage, enables application modules or applets to be dynamicallytransmitted to the client device and allows the user interaction withthese applets. 3) Microbrowser, which is a lightweight applicationresident on the wireless terminal that controls the user interface andinterprets the WML/WMLScript content. 4) A lightweight protocol stack402 which minimizes bandwidth requirements, guaranteeing that a broadrange of wireless networks can run WAP applications. The protocol stackof WAP can comprise a set of protocols for the transport (WTP), session(WSP), and security (WTLS) layers. WSP is binary encoded and able tosupport header caching, thereby economizing on bandwidth requirements.WSP also compensates for high latency by allowing requests and responsesto be handles asynchronously, sending before receiving the response toan earlier request. For lost data segments, perhaps due to fading orlack of coverage, WTP only retransmits lost segments using selectiveretransmission, thereby compensating for a less stable connection inwireless. The above mentioned features are industry standards adoptedfor wireless applications, and well known to those skilled in the art.

The presently preferred embodiment utilizes WAP, because WAP has thefollowing advantages, 1) WAP protocol uses less than one-half the numberof packets that the standard HTTP or TCP/IP Internet stack uses todeliver the same content. 2) Addressing the limited resources of theterminal, the browser, and the lightweight protocol stack are designedto make small claims on CPU and ROM. 3) Binary encoding of WML andSMLScript helps keep the RAM as small as possible. And, 4) Keeping thebearer utilization low takes account of the limited battery power of theterminal.

In this embodiment two modes of communication are possible. In thefirst, the server initiates an upload of the actual parameters beingapplied to the patient, receives these from the stimulator, and storesthese in its memory, accessible to the authorized user as a dedicatedcontent driven web page. The web page is managed with adequate securityand password protection. The physician or authorized user can makealterations to the actual parameters, as available on the server, andthen initiate a communication session with the stimulator device todownload these parameters.

The physician is also able to set up long-term schedules of stimulationtherapy for their patient population, through wireless communicationwith the server. The server in turn communicates these programs to theneurostimulator. Each schedule is securely maintained on the server, andis editable by the physician and can get uploaded to the patient'sstimulator device at a scheduled time. Thus, therapy can be customizedfor each individual patient. Each device issued to a patient has aunique identification key in order to guarantee secure communicationbetween the wireless server 130 and stimulator device 42.

In this embodiment, two modes of communication are possible. In thefirst, the server initiates an upload of the actual parameters beingapplied to the patient, receives these from the stimulator, and storesthese in its memory, accessible to the authorized user as a dedicatedcontent driven web page. The physician or authorized user can makealterations to the actual parameters, as available on the server, andthen initiate a communication session with the stimulator device todownload these parameters.

Shown in conjunction with FIG. 36, in one embodiment, the externalstimulator 42 and/or the programmer 85 may also be networked to acentral collaboration computer 286 as well as other devices such as aremote computer 294, PDA 140, phone 141, physician computer 143. Theinterface unit 292 in this embodiment communicates with the centralcollaborative network 290 via land-lines such as cable modem orwirelessly via the internet. A central computer 286 which has sufficientcomputing power and storage capability to collect and process largeamounts of data, contains information regarding device history andserial number, and is in communication with the network 290.Communication over collaboration network 290 may be effected by way of aTCP/IP connection, particularly one using the internet, as well as aPSTN, DSL, cable modem, LAN, WAN or a direct dial-up connection.

The standard components of interface unit shown in block 292 areprocessor 305, storage 310, memory 308, transmitter/receiver 306, and acommunication device such as network interface card or modem 312. In thepreferred embodiment these components are embedded in the externalstimulator 42 and can also be embedded in the programmer 85. These canbe connected to the network 290 through appropriate security measures(Firewall) 293.

Another type of remote unit that may be accessed via centralcollaborative network 290 is remote computer 294. This remote computer294 may be used by an appropriate attending physician to instruct orinteract with interface unit 292, for example, instructing interfaceunit 292 to send instruction downloaded from central computer 286 toremote implanted unit.

Shown in conjunction with FIG. 37A the physician's remotecommunication's module is a Modified PDA/Phone 140 in this embodiment.The Modified PDA/Phone 140 is a microprocessor based device as shown ina simplified block diagram in FIGS. 37A and 37B. The PDA/Phone 140 isconfigured to accept PCM/CIA cards specially configured to fulfill therole of communication module 292 of the present invention. The ModifiedPDA/Phone 140 may operate under any of the useful software includingMicrosoft Window's based, Linux, Palm OS, Java OS, SYMBIAN, or the like.

The telemetry module 362 comprises an RF telemetry antenna 142 coupledto a telemetry transceiver and antenna driver circuit board whichincludes a telemetry transmitter and telemetry receiver. The telemetrytransmitter and receiver are coupled to control circuitry and registers,operated under the control of microprocessor 364. Similarly, withinstimulator a telemetry antenna 142 is coupled to a telemetry transceivercomprising RF telemetry transmitter and receiver circuit. This circuitis coupled to control circuitry and registers operated under the controlof microcomputer circuit.

With reference to the telecommunications aspects of the invention, thecommunication and data exchange between Modified PDA/Phone 140 andexternal stimulator 42 operates on commercially available frequencybands. The 2.4-to-2.4853 GHz bands or 5.15 and 5.825 GHz, are the twounlicensed areas of the spectrum, and set aside for industrial,scientific, and medical (ISM) uses. Most of the technology todayincluding this invention, use either the 2.4 or 5 GHz radio bands andspread-spectrum technology.

The telecommunications technology, especially the wireless internettechnology, which this invention utilizes in one embodiment, isconstantly improving and evolving at a rapid pace, due to advances in RFand chip technology as well as software development. Therefore, one ofthe intents of this invention is to utilize “state of the art”technology available for data communication between Modified PDA/Phone140 and external stimulator 42. The intent of this invention is to use3G technology for wireless communication and data exchange, even thoughin some cases 2.5G is being used currently.

For the system of the current invention, the use of any of the “3G”technologies for communication for the Modified PDA/Phone 140, isconsidered within the scope of the invention. Further, it will beevident to one of ordinary skill in the art that as future 4G systems,which will include new technologies such as improved modulation andsmart antennas, can be easily incorporated into the system and method ofcurrent invention, and are also considered within the scope of theinvention.

1. A method of providing electrical pulses with rechargeable implantablepulse generator for nerve blocking with or without selective electricalstimulation of vagus nerve(s) or its branches or part thereof fortreating, controlling, or alleviating the symptoms for at least one ofobesity, motility disorders, eating disorders, inducing weight loss,FGIDs, gastroparesis, gastro-esophageal reflex disease (GERD),pancreatitis, and ileus, comprising the steps of: providing saidrechargeable implantable pulse generator, comprising a microcontroller,pulse generation circuitry, rechargeable battery, battery rechargingcircuitry, and a coil; providing a lead with at least two electrodesadapted to be in contact with said nerve tissue, and in electricalcontact with said rechargeable implantable pulse generator; providing anexternal power source to charge said rechargeable implantable pulsegenerator; and providing an external programmer to program saidrechargeable implantable pulse generator.
 2. A method of claim 1,wherein said nerve blocking comprises selective blocking of nerveimpulses of a vagus nerve(s), its branch(es) or part thereof, at one ormore sites with said electrical pulses.
 3. A method of claim 1, whereinsaid electrical pulses are for at least one of afferent block, efferentblock, or organ block.
 4. A method of claim 1, wherein nerve blockingmay also be provided to alleviate the side effects of nerve stimulationtherapy.
 5. A method of claim 1, wherein said nerve blocking comprisesat least one from a group consisting of: DC or anodal block, Wedenskiblock, and Collision block.
 6. A method of claim 1, wherein saidrechargeable implantable pulse generator further comprisesstimulus-receiver means such that, said implantable rechargeable pulsegenerator can also function in conjunction with an external stimulator,to provide said electrical pulses for said nerve blocking and/orstimulation.
 7. A method of claim 1, wherein said external power sourceto recharge said rechargeable implantable pulse generator can be anexternal re-charger or an external stimulator.
 8. A method of claim 1,wherein said coil used in recharging said pulse generator is around saidimplantable rechargeable pulse generator case in a silicone enclosure.9. A method of claim 1, wherein said rechargeable implanted pulsegenerator further comprises one or two feed-through(s) for externalizingcoils, for unipolar or bipolar configurations respectively.
 10. A methodof claim 1, wherein said at least two electrodes are made of a materialselected from the group consisting of platinum, platinum/iridium alloy,platinum/iridium alloy coated with titanium nitride, and carbon.
 11. Amethod of claim 1, wherein said rechargeable battery comprises at leastone of lithium-ion, lithium-ion polymer batteries.
 12. A method of claim1, wherein said rechargeable implanted pulse generator is adapted to beremotely interrogated and/or programmed over a wide area network by anexternal interface means.
 13. A method of providing electrical pulseswith rechargeable implantable pulse generator for vagal blocking with orwithout selective vagal stimulation for treating or alleviating thesymptoms for at least one of obesity, eating disorders, inducing weightloss, FGIDs, gastroparesis, gastro-esophageal reflex disease (GERD),pancreatitis, and ileus, comprising the steps of: providing animplantable rechargeable pulse generator, wherein said implantablerechargeable pulse generator comprises a stimulus-receiver means, and animplantable pulse generator means comprising a microcontroller, pulsegeneration circuitry, rechargeable battery, and battery rechargingcircuitry; providing a lead with at least two electrodes adapted to bein contact with said vagus nerve(s) or its branches or part thereof, andin electrical contact with said implantable rechargeable pulsegenerator; providing an external power source to charge rechargeableimplantable pulse generator; and providing an external programmer toprogram the said rechargeable implantable pulse generator.
 14. A methodof claim 13, wherein said rechargeable implantable pulse generator canfunction in conjunction with an external stimulator, to provide saidblocking to said vagus nerve(s) and/or its branches with or without saidselective stimulation.
 15. A method of claim 13, wherein said coil usedin recharging said pulse generator is around said rechargeableimplantable pulse generator case in a silicone enclosure.
 16. A methodof claim 13, wherein said rechargeable battery comprises at least one oflithium-ion, lithium-ion polymer batteries.
 17. A system for providingelectrical pulses with rechargeable implantable pulse generator fornerve blocking with or without selective electrical stimulation of vagusnerve(s) or its branches or part thereof for treating, controlling, oralleviating the symptoms for at least one of obesity, motilitydisorders, eating disorders, inducing weight loss, FGIDs, gastroparesis,gastro-esophageal reflex disease (GERD), pancreatitis, and ileus,comprising: a rechargeable implantable pulse generator, comprising, amicroprocessor, pulse generation circuitry, rechargeable battery,battery recharging circuitry, and a coil; a lead with at least twoelectrodes adapted to be in contact with said nerve tissue and inelectrical contact with said implantable rechargeable pulse generator;an external power source to charge said rechargeable implantable pulsegenerator; and an external programmer to program said rechargeableimplantable pulse generator.
 18. A system of claim 17, wherein saidnerve blocking comprises at least one from a group consisting of: DC oranodal block, Wedenski block, and Collision block.
 19. A system of claim17, wherein said coil is used for bidirectional telemetry, or receivingelectrical pulses from said external stimulator.
 20. A system of claim17, wherein said coil used in recharging said pulse generator is aroundsaid rechargeable implantable pulse generator case in a siliconeenclosure.
 21. A system of claim 17, wherein said rechargeable implantedpulse generator further comprises one or two feed-through(s) forexternalizing coils, for unipolar or bipolar configurationsrespectively.
 22. A system of claim 17, wherein said implantablerechargeable pulse generator further comprises stimulus receiver meanssuch that said implantable rechargeable pulse generator can alsofunction in conjunction with an external stimulator, to provide saidblocking with or without stimulation to said vagus nerve(s) and/or itsbranches.
 23. A system of claim 17, wherein said at least two electrodesare made of a material selected from the group consisting of platinum,platinum/iridium alloy, platinum/iridium alloy coated with titaniumnitride, and carbon.
 24. A system of claim 17, wherein said rechargeablebattery comprises at least one of lithium-ion, lithium-ion polymerbatteries.
 25. A system of claim 17, wherein said rechargeable implantedpulse generator is adapted to be remotely interrogated and/or programmedover a wide area network by an external interface means.